It is much more than that. The
San Antonio River is below street level as it wanders through the
downtown area. Yes, it is the major
tourist attraction in the city, but it was originally conceived as a
flood-control project in the 1920s, and was built with a lot of
WPA manpower. The banks are lined with restaurants, and one river-branch terminates in a
mall. You can ride on the river on
electric-powered tourist boats, and the
park rangers have their own boats.
It is my understanding that Oklahoma City just funded a project to create their own Riverwalk because their studies show San Antonio's to be so successful.